WO2004045041A1

WO2004045041A1 - Control device for automatic machine

Info

Publication number: WO2004045041A1
Application number: PCT/JP2003/014234
Authority: WO
Inventors: Michiharu Tanaka; Keijiro Yuasa
Original assignee: Kabushiki Kaisha Yaskawa Denki
Priority date: 2002-11-12
Filing date: 2003-11-07
Publication date: 2004-05-27
Also published as: SE529062C2; TWI272167B; JP4003124B2; US20060202556A1; SE0501006L; JP2004166357A; TW200413143A; SE529062C8; DE10393689T5

Abstract

A control device for an automatic machine, performing highly reliable power supply to a drive device for the automatic machine and not having problem in securing safety. A control device for an automatic machine has a breaker (22) connected to a power source (21) and a drive device (32) for supplying electric power to a drive portion (35) of the automatic machine through a relay device (31) connected to the breaker (22), and the control device controls the drive device (32). The control device also has a current control rectifier element (33) connected to the relay device (31) and a current controller (29) for controlling current to the current control rectifier element (33) after the relay device (31) is closed at the time when the power to a drive portion (35) is on.

Description

Specification

Prepared by the International Searching Authority as shown below.

Control devices for automatic machinery

[Technical field]

The present invention relates to power-on and power-off control of a drive device in a control device of an automatic machine. '

[Background technology]

In a small component processing machine using an automatic machine such as a robot, an operator may supply and remove processed components to and from a processing position. In this case, a part of the worker's body enters the movable range of the automatic machine, so if the automatic machine performs an unexpected operation such as runaway, approach of the automatic machine to the worker with a light curtain etc. Is detected and worker safety is ensured, such as by shutting off the drive power of the automatic machine. In order to increase safety awareness in recent years and reduce the cost of automatic machinery, safety devices have been reduced. The safety of workers is ensured by turning off the drive power of the machine. The drive power is turned on and off each time parts are supplied or removed after work, and the life of the relay contacts needs to be greatly extended. '

The drive shafts that control multiple axes used in automatic machines include a rectifier circuit that converts AC to DC connected to a relay device such as an electromagnetic contactor, a smoothing capacitor that smoothes the rectified voltage, and a smoothing capacitor. It is composed of a plurality of inverter circuits for converting the subsequent DC voltage. The inverter is controlled by a PWM command signal generated by the CPU based on the operation of the automatic machine. The smoothing circuit is provided with a smoothing capacitor. In this capacitor input type circuit, a large charging current flows through the smoothing capacitor when the power is turned on, and there is a possibility that the relay device contacts and the rectifying element of the rectifying circuit may be damaged.

(Conventional example 1)

When the power is turned on, the current from the power supply to the rectifier is bypassed to the resistor to reduce the inrush current and charge the smoothing capacitor.When the current decreases, the relay connected across the resistor is closed and the rectifier is connected directly to the power supply. Connect to Alternatively, the same effect can be obtained by monitoring the smoothed voltage and closing the relay contact when the voltage exceeds a predetermined voltage. This will be described with reference to FIG. FIG. 3 is a block diagram illustrating an inverter device 62 for controlling the number of revolutions of a compressor 66 and a control system thereof. The inverter device 62 includes a rectifier circuit portion 63, a smoothing capacitor 64, and an inverter portion 65. Reference numeral 67 denotes an input current sensor for detecting the input current of the inverter device 62, and reference numeral 68 denotes an input current conversion circuit for converting the detected current into a digital signal and inputting it to a control device (microcomputer) 69. When power is supplied from the AC power supply 61 to the inverter device 62, first, the smoothing capacitor 64 is charged. Reference numeral 71 denotes a resistance element for suppressing the rush current at the start of charging. In the microcomputer 69, the smoothing capacitor 64 is charged and the input current value is programmed in advance. The drive circuit 73 is controlled to turn on the relay 72 when the value falls below the determined judgment reference value. (Refer to Japanese Patent Application Laid-Open No. Hei 5_1 168 248)

(Conventional example 2)

As another prior art, there is an invention relating to an opening operation of a relay contact when a power supply is cut off. The problem with conventional example 1 is that if the contacts of the relay are opened when a large current is flowing when the power is cut off, an arc is generated between the contacts, causing the contact surface to be rough and causing a failure. ing. This is to control the power supply to the drive device, and to cut off the drive when the current is equal to or more than a predetermined value when the drive is cut off. When the current decreases, the contacts are opened. This will be described in detail with reference to FIG. Current value detecting means 82 for detecting the contact current of the relay 8; and when the current detected by the current value detecting means 82 exceeds a predetermined reference value, the opening operation of the relay contact is opened and the current is detected. A control unit 83 for opening the relay contact when the current value detected by the value detection means 82 becomes equal to or less than the reference value. (Refer to Japanese Patent Application Laid-Open No. 11-1997-176).

(Conventional example 3)

Another conventional example is a method of opening and closing a relay contact near zero volts of an AC power supply. (Refer to Japanese Patent Application Laid-Open No. 2000-340400)

In Conventional Example 1, when power is turned on, a large inrush current is suppressed by supplying power through a resistor.However, if the resistance of the resistor is increased, the charging time for the smoothing capacitor increases, and the motor can be driven by the inverter. The time until it becomes longer. This is because the time from when the drive power is turned on to when the automatic machine can start operating increases, so the time per processed part increases.Therefore, considering the productivity, reduce the resistance value of the resistor. However, it is desirable to reduce the time until the automatic machine can start operation. However, reducing the resistance value makes it impossible to sufficiently suppress the inrush current, so each time the drive power supply is turned on, the resistor conductor heats up instantaneously due to its own heat, and the relay is closed after the circuit is closed. Therefore, the resistor conductor cools. The resistor conductor repeatedly expands and contracts due to the heat at this time, and a disconnection failure may occur due to metal fatigue. For this reason, it is necessary to select a resistor with a large capacity, that is, a resistor with a large external shape, which is a major obstacle when miniaturization of the control device of an automatic machine is desired. There are also obstacles to cost reduction. In addition, because there is no countermeasure when the power supply is shut down, an operation such as an emergency stop is performed while the motor is running. The contact surface may be roughened due to the occurrence of welding, which may shorten the service life of the contact when fusion or welding occurs.

In Conventional Example 2, the contacts are opened immediately after the current falls below a predetermined value.However, as a means of ensuring safety in automatic machinery, the drive power to the motor is shut off by an emergency stop operation or the like in an emergency. Since the operation is performed by stopping the operation of the automatic machine, if an emergency stop operation that shuts off the drive power is performed, it is necessary to open the relay contact regardless of whether the automatic machine is operating or stopped. The current during the operation or acceleration of the automatic machine is less than the specified value. Patent Literature 2, which does not open when the load is large, cannot be applied to turning on and off the drive power of the robot. When the current detector is arranged in an AC circuit, the same open control of the relay contact as in the conventional example 3 is performed. However, in Conventional Example 3, the relay contacts are opened and closed near the zero port of the AC power supply. However, when the contacts are closed, the charging current to the smoothing capacitor flows as an inrush current, so the contact capacity is sufficient. Is required. In addition, when the circuit is open, the load is capacitive due to the presence of the smoothing capacitor, so the current cannot be completely cut off at the moment of opening, and an arc is generated at the contact. .

In the above conventional example, a relay device with a large contact capacity is selected so that it is suitable for the switching frequency of the relay device contacts against the inrush current when the contacts are closed and the arc generated between the contacts when the contacts are opened and closed. Forces that have taken measures This method has a problem in that the size of the control device has to be increased when it is applied to the control device of an automatic machine that requires the outer shape of the relay device to be larger and smaller. In addition, there was a problem that the cost would increase.

[Disclosure of the Invention]

Therefore, the present invention has been made in view of such problems, and provides a highly reliable power supply to a drive device of an automatic machine and a control of the automatic machine which does not hinder safety assurance. It is intended to provide a device.

In order to solve the above problem, the present invention is configured as follows.

A control device for an automatic machine according to a first invention includes a circuit breaker connected to a power supply, and a drive device for supplying power to a drive unit of the automatic machine via a relay device connected to the circuit breaker. A control device for an automatic machine for controlling the drive device, wherein the current control rectifier device connected to the relay device and the current control rectifier device after closing of the relay device when the drive unit is turned on. And a current controller for controlling energization of the power supply.

A control device for an automatic machine according to a second invention includes a circuit breaker connected to a power supply, and a drive device for supplying power to a drive unit of the automatic machine via a relay device connected to the circuit breaker. In the control device for an automatic machine for controlling the driving device, the current control rectifier element connected to the relay device and the current control rectifier before disconnection of the relay device when the drive unit is turned off. A current controller for deenergizing the element. As described above, according to the control device for an automatic machine of the present invention, when the drive power is turned on, the contact of the relay is closed, and then the current control rectifying element is used to adjust the start angle of the AC voltage. By doing this, the relay contact can be closed without voltage, the rush current can be suppressed, damage to the relay contact can be prevented, and the current control rectifier can be energized when the drive power is cut off. After stopping the control and turning off the power, the contacts of the relay device are opened, suppressing the arc generated in the contact circuit and preventing the contacts of the relay device from roughening, greatly extending the life of the relay device contacts. There is an effect that can be. [Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a robot system according to an embodiment of the present invention. FIG. 2 is a block diagram of a driving device and a control unit according to the embodiment of the present invention. FIG. 3 is a flowchart for turning on the drive power supply in the embodiment of the present invention. FIG. 4 is a flow chart of the drive power cutoff in the embodiment of the present invention. FIG. 5 shows a drive device power supply control circuit in the embodiment of the present invention. FIG. 6 is a configuration diagram of the first conventional example. FIG. 7 is a configuration diagram of the second conventional example. ,

[Best Mode for Carrying Out the Invention]

Hereinafter, a case of a robot control device as a specific embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram illustrating a configuration of a robot control device and a system according to a first embodiment of the present invention.

In the figure, reference numeral 1 denotes a robot, which is connected to a robot controller 2. A work tool for performing work is attached to the tip of the wrist of the robot 1. In the robot controller 2, the robot 1 is operated by the operation at the time of teaching, the position is registered, or the work is registered, so that the work program is registered or the registered work program is changed. Pendant 3 is connected to perform editing. In addition, a protective fence 4 surrounding the operation area of the robot 1, a protective fence door 5 at the entrance to the protective fence 4, and a door open / close detection device 6 for detecting the open / close state of the protective fence door 5 are provided. The device 6 is connected to the robot control device 2. The robot control device 2 is provided with an operation panel 7 for giving an emergency stop switch, a mode change of the robot system, an operation start command, and a stop command to the robot control device 2. Reference numeral 8 denotes an external operation device, which is connected to the mouth pot control device 2 and, like the operation panel 7, sends an emergency stop switch, a mode change of the robot system, an operation start command, and a stop command to the robot control device 2. The worker 9 mounts the work 11 to be machined on the worktable 10 or removes the work 11 after the work by the robot 1 from the opening of the protective fence 4 (not shown). At this time, since at least a part of the body of the worker 9 comes into the movable range of the robot 1, the drive power of the robot 1 is controlled by an emergency stop operation of the external operation device 8 to secure the safety of the worker 9. After shutting off.

FIG. 2 is a block diagram showing a driving device for implementing the present invention and a control unit thereof. In the figure, reference numeral 21 denotes a power supply for controlling and driving the robot. The power supply 21 is drawn into the robot control device 2, and the circuit breaker 22 turns on and off the power to the robot control device 2. Reference numeral 23 denotes a control power supply unit which is connected to the load side of the circuit breaker 22 ′ and supplies necessary power to the control board 24. In addition, the power supply 21 is connected to the control power supply 23 from the load side of the circuit breaker 22, is branched for driving, is connected to the relay 31, and is connected to the drive unit 32 from the load side. You are being led. The control board 24 is a CPU and memory 25 that controls and controls the robot system, and an input / output interface that exchanges signals with the operation panel 7 or the external operation device 8. Interface 26, which issues control signals to the relay 31, which turns on and off the power to the drive 32, and the drive 32, the interrupter 22 to the drive 32, and the relay 3

It comprises a current controller 29 for performing rectification control of an AC power supply 21 input via 1 and a drive voltage interface 28 for detecting a rectified and smoothed drive voltage. The components of the control board 24 other than those relating to the present invention are not shown. In the drive unit 32, the current is controlled by the current control rectifying element 33 under the control of the current controller 29, rectified by the smoothing unit 34, and the drive units 35-1, 35 that drive each axis drive motor (not shown) of the robot 1 -2

35-n is connected to the drive unit 35-1, 3.5-2, 35-n is the control of the control board 24

Drive each axis drive motor of robot 1 based on '. (The control signal of the drive unit is not shown.) Next, the operation of each component when the drive power supply is turned on in the embodiment of the present invention will be described with reference to a flowchart shown in FIG.

When a drive power-on instruction is input from the operator 9 to the external operation device 8 (S1), the CPU can turn on the drive power from the emergency stop operation status, the robot system mode, and the protection fence door 5 status. Check if it is possible, and if it is possible to turn on the drive power, proceed to the step of turning on the drive power.If not, ignore the drive power on command and turn on the drive power. Absent. (S2) Next, the contact of the relay device 31 is closed to connect the input power source 21 to the drive device 32. At this time, since the current controller 29 does not control the current control rectifier 33 of the drive device β 2, the current does not flow through the contacts of the relay device 31. There is no arcing or inrush current flowing through the. (S3) Next, the current controller 29 starts and starts the energization control of the current control rectifying element 33. The current controller 29 adjusts the energization start angle of the AC voltage based on the voltage across the smoothing device 34 after the rectification. No excessive inrush current flows. (S4) At this time, if the voltage between both ends of the smoothing device 34 obtained by the driving voltage interface 28 does not rise for a predetermined time, the driving units 35-1, 35-2, 35-η It is also possible to detect the occurrence of a short circuit in the wiring or the occurrence of a failure in the short circuit mode of the drive unit 35-1, 35-2, 35-η. Next, the voltage between both ends of the smoothing device 34 acquired by the drive voltage interface 28 can be controlled by a preset voltage, that is, a drive unit 35-1, 35-2, 35-η. After reaching the appropriate voltage, drive control of each axis drive motor is performed. (S 5)

Next, the operation of each component when the drive power supply is cut off in the embodiment of the present invention will be described with reference to a flowchart shown in FIG.

When a drive power cutoff instruction such as an operation of an emergency stop switch is input from the operator 9 to the external operation device 8 (S11), the current controller 29 reduces the rectification current of the current control rectifier 33 and de-energizes the current. Then (S12), the contact of the relay 31 is opened. (S1 3)

FIG. 5 shows a drive device power supply control circuit showing a relay device interface .27 for controlling the turning on and off of power to a drive device 32 for carrying out the present invention, and an input / output interface 26. In the figure, 41 is the emergency stop switch of the external operation device, 43 is the pendant emergency stop switch, and 45 is the pendant 3 that drives each axis when the robot 1 operates. An enable switch for securing the operator's safety when driving the motor, 47 is a door open / close detection switch, and these switches are connected to the input / output interface 26, and each is an external operation device emergency stop relay. 42, Pendant emergency stop relay 44, Enable switch relay 46, Door open / close relay 48 Note that the enable switch 45 is closed when each drive shaft motor is driven, and the door open / close detection switch 47 is closed when the door is closed. In addition to these relays, there are a plurality of control relays (not shown) which are controlled by the CPU status or by the CPU. The connection of the contacts of these relays is as follows. 24 Closed when the CPU is normal from the 4 V control power supply.CPU normal relay contact 52, external operation device emergency stop relay contact 42a, pendant emergency stop relay contact 44a are connected in series, and enable switch relay is connected. Circuits connected in series with contacts 4 6 a and teaching mode relay contacts 5 0 that close when the teaching mode is selected, and one contact 4 9 and a door opening / closing relay contact 4 that close when the automatic machine is in operation mode The circuits connected in series at 8a are connected in parallel and are connected to the other of the pendant emergency stop relay contacts 44a. The drive power control relay contact 51 is connected to the above-mentioned circuit, and from the other side, the CPU reads the signal status via the input interface circuit 53, and is connected in parallel to the relay control relay 54, which is an off-delay relay. The relay control relay contact 54a signal controls the contact switching of the relay 31 via the relay interface 27.

In this circuit, when the emergency stop of the external operating device 8 is operated as the drive power supply instruction, the emergency stop switch 41 of the external operating device is opened, and the external operating device emergency stop relay 42 is turned off. Since the external operation device emergency stop relay contact 4 2a is open, the input interface circuit 53 input becomes non-voltage, so that the CPU recognizes that the drive power-on instruction has been received. CPU reduces the rectified current of the current control rectifier 33 via the current controller 29 and deactivates it. While the rectified current of the current control rectifier 33 is reduced by the CPU and the power is not supplied, the relay control relay 54 is an off-delay relay. (For example, 0.1 second), the contacts of the relay device 31 are opened via the relay device interface 27, and the supply of power to the drive device 32 is cut off.

[Industrial applicability]

An automatic machine equipped with a drive shaft, which is useful for extending the life of a relay of a control device in which the power of the drive shaft is repeatedly turned on and off frequently.

Claims

The scope of the claims

1. An automatic machine that has a circuit breaker connected to a power supply, and a driving device that supplies power to a driving unit of the automatic machine via a relay device connected to the circuit breaker, and controls the driving device. In the control device of

A current control rectifier connected to the relay device;

A current controller for controlling the energization of the current control rectifier after the relay is closed when the power of the drive unit is turned on. '

2. An automatic machine that has a circuit breaker connected to a power supply, and a driving device that supplies power to a driving unit of the automatic machine via a relay device connected to the circuit breaker, and controls the driving device. In the control device of

A current control rectifier connected to the relay device;

And a current controller configured to de-energize the current control rectifying element before the relay device is opened when the power supply of the driving unit is cut off.